python - 从子类访问python父类变量

Question

为什么这行不通？

class Parent:
    __var = "Whatever"

class Child(Parent):
    def printVar(self):
        print(self.__var)


Timmy = Child()

Timmy.printVar()

我得到以下异常:

Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "<stdin>", line 3, in printVar
AttributeError: 'Child' object has no attribute '_Child__var'

Answer 1

这是因为您选择使用双前导下划线命名属性。这会触发一些名称修改

您可以通过 self._Parent__var 访问它

In [8]: class Parent:
    __var = "Whatever"
   ...:     
In [9]: class Child(Parent):
    def foo(self): print self._Parent__var
   ...:     
In [10]: a=Child()
In [11]: a.foo()
Whatever

更多信息可在 python 文档中找到，网址为 https://docs.python.org/2/tutorial/classes.html#private-variables-and-class-local-references